Our central theme is to study non-traditional mechanisms of atherogenesis. The genetic basis and heterogeneity of hyperapoB and its linkage to the apoB, A-I/CIII/AIV gene complex, and lipoprotein lipase genes will be studied. The role of traditional and non-traditional (i.e., DHEAS, homocyst(e)ine, Lp(a) and apoB and A1) risk factors for CAD will be studied in black and white men and women. The biochemical basis of hyperapoB will be studied by elucidating the primary and secondary structures of serum basic proteins (BP) I, II and III and by cloning, sequencing and mapping the cDNAs for BP I, II and III. The specific biochemical mechanism of the acylation stimulatory activity of BP I, II and III and its relation to high affinity binding and uptake in cultured fibroblasts will be studied. Metabolic turnover studies of very low density lipoproteins (VLDL) and the clearance of intestinally-derived lipoproteins and their atherogenicity will be studied in the same normal and hyperapoB subjects. The basis for elevated apoB levels in the Johns Hopkins colony of St. Thomas Hospital (JH-STH) rabbits will be studied by in vivo VLDL turnover studies, secretion and synthesis of apoB in hepatocytes, complex segregation analysis and the use of cDNA clones for the apoB gene; the effect of these parameters, and of cholesterol feeding on atherosclerosis in these animals will be determined. The effect of oxidized LDL and lactosylceramide (LacCer) on the induction of cell proliferation in arterial smooth muscle cells via its effect on UDP-Gal, GlcCer:B1-->4 galactosyltransferase (GalT- 2) and on growth factors will be determined. The role of oxidized LDL, LacCer, triglyceride-rich lipoproteins and cholesterol feeding on endothelial cell dysfunction via the pertussin toxin sensitive G1 transduction pathway will be studied using a porcine bioassay model. Our overall goal is to understand the genetic, biochemical and metabolic factors that regulate non-traditional risk factors for atherosclerosis.